On Wed,4/15/2015 11:32 PM, Don Jones wrote:
With everything being 50 ohms the performance of the bandpass filters
and coaxial stub filters were flawless.
BS. Everything is 50 ohms ONLY at the fundamental frequency for the
antenna. At ANY other frequency, everything, both transmitter and
antenna, is VERY different from 50 ohms resistive.
For the CA QSO Party, we operate CW and SSB on the same bands with K3s
and 600W power amps, usually KPA500s. We are able to operate on the same
bands, 20, 15, and 10M with about 200 ft separation with 2-element or
3-element Yagis that are approximately inline with each other (that is,
each is at 90 degrees to the other), and about 400 ft separation of
dipoles on 40M and 80./75 M. EVERY feedpoint has a SERIOUS common mode
choke, and, as noted, the radios are K3s. You could not do that with
lradios or power amps of lesser quality.
At home, under controlled conditions, I can run 1.5 kW with K3s driving
Ten Tec Titan 425s into 3-el Yagis on the same band about 200 ft apart
within about 100 kHz if those Yagis are at inline with each other. They
satisfy that condition aiming about 70 degrees. This is the result of 1)
VERY clean radios; 2) VERY clean power amps; 3) VERY bulletproof
receivers; 4) antenna directivity; serious common mode chokes on each
antenna at the feedpoint; and 5) high quality coax (in this case, 7/8
hard line or 1/2-in CATV hard line) and high quality patch cables inside
the shack. The Titan 425s were designed around 1978, but they got it right.
At that CQP site, every cable is high quality RG8 or RG11, and every
connector is hand soldered.
73, Jim K9YC
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